FIG. 1 depicts a portion of a conventional magnetic transducer 10, such as a conventional read transducer or other device. The conventional transducer 10 includes a conventional hard bias layer 16 and a conventional seed layer 14 that may reside on a conventional insulator 12. The conventional read transducer 10 would typically include also a conventional bottom shield, a read sensor, conventional leads, conventional insulator, and a conventional top shield, which are not shown for clarity.
The conventional seed layer 14 is formed prior to the conventional hard bias layer 16. The seed layer 14 is desired to provide a surface suitable for growth of the conventional hard bias layer 16. The conventional seed layer 14 is typically composed of a layer of Cr, CrV, or CrTi. Alternatively, the conventional seed layer 14 may be a bilayer including a Ta underlayer (not separately shown) and a W layer (not separately shown) between the conventional hard bias layer 16 and the Ta underlayer. The Ta underlayer is typically amorphous, while the upper W layer is crystalline. The conventional seed layer 14 is typically formed by sputtering the Cr, CrV, CrTi, W and/or Ta in a Xe gas plasma.
The conventional hard bias layer 16 may be used to magnetically bias the read sensor (not shown in FIG. 1). For example, the conventional magnetic hard bias structure 16 may ensure that the free layer (not shown) of the read sensor is stable and single domain. To ensure the stability of the read sensor, the conventional magnetic hard bias layer 16 should not be affected by external magnetic fields, for example from the recording media or write transducer, and be stable throughout operation. The conventional hard bias layer 16 is thus desired to have a high remanence magnetization, a large coercivity, and be thermally stable. Materials such as CoPt and CoCrPt are thus generally selected for use in the hard bias structure 16 and deposited in a Xe plasma. For such materials to have the desired magnetic properties, a high degree of in-plane crystallographic orientation and relatively small grain size are desired. Consequently, the conventional seed layer 14 is used.
Although the conventional hard bias layer 16 functions, one of ordinary skill in the art will recognize that there are drawbacks. In particular, the magnetization of the conventional hard bias layer 16 may be disturbed during operation of the conventional magnetic read transducer. As a result, the free layer may be destabilized. Consequently, performance of the conventional magnetic transducer may be adversely affected
Accordingly, what is needed is a system and method for providing an improved hard bias structure.